Scientists find evidence for 'chronesthesia,' or mental time travel

December 22, 2010

Researchers have found evidence for "chronesthesia," which is the brain's ability to be aware of the past and future, and to mentally travel in subjective time. They found that activity in different brain regions is related to chronesthetic states when a person thinks about the same content during the past, present, or future.
(PhysOrg.com) -- Scientists refer to the brain's ability to think about the past, present, and future as "chronesthesia," or mental time travel, although little is known about which parts of the brain are responsible for these conscious experiences. In a new study, researchers have used functional magnetic resonance imaging (fMRI) to investigate the neural correlates of mental time travel and better understand the nature of the mental time in which the metaphorical "travel" occurs.
The researchers, Lars Nyberg from Umea University in Sweden; Reza Habib from Southern Illinois University in Illinois; and Alice S. N. Kim, Brian Levine, and Endel Tulving from the University of Toronto in Ontario, have published their results in a recent issue of the Proceedings of the National Academy of Sciences.
"Mental time travel consists of two independent sets of processes: (1) those that determine the contents of any act of such 'travel': what happens, who are the 'actors,' where does the action occur; it is similar to the contents of watching a movie - everything that you see on the screen; and (2) those that determine the subjective moment of time in which the action takes place - past, present, or future," Tulving told PhysOrg.com.
"In cognitive neuroscience, we know quite a bit about perceived, remembered, known, and imagined space," he said. "We know essentially nothing about perceived, remembered, known, and imagined time. When you remember something that you did last night, you are consciously aware not only that the event happened and that you were 'there,' as an observer or participant, but also that it happened yesterday, that is, at a time that is no more. The question we are asking is, how do you know that it happened at a time other than 'now'?"
In their study, the researchers asked several well-trained subjects to repeatedly think about taking a short walk in a familiar environment in either the imagined past, the real past, the present, or the imagined future. By keeping the content the same and changing only the mental time in which it occurs, the researchers could identify which areas of the brain are correlated with thinking about the same event at different times.
The results showed that certain regions in the left lateral parietal cortex, left frontal cortex, and cerebellum, as well as the thalamus, were activated differently when the subjects thought about the past and future compared with the present. Notably, brain activity was very similar for thinking about all of the non-present times (the imagined past, real past, and imagined future).Because mental time is a product of the human brain and differs from the external time that is measured by clocks and calendars, scientists also call this time "subjective time." Chronesthesia, by definition, is a form of consciousness that allows people to think about this subjective time and to mentally travel in it.
Tulving said, "The concept of 'chronesthesia' is essentially brand new. Therefore, I would say, the most important result of our study is the novel finding that there seem to exist brain regions that are more active in the (imagined) past and the (imagined) future than they are in the (imagined) present. He added that, at this stage of the game, it is too early to talk about potential implications or applications of understanding how the brain thinks about the past, present, and future.
"Our study, we hope, is the first swallow of the spring, and others will follow," he said.

Excerpt from www.PhysOrg.com